| 摘要 |
The invention concerns apparatus for controlling a flow of pressure fluid, the apparatus comprising a chamber having an inlet and an outlet through which the pressure fluid may respectively be supplied to and may issue from the interior of the chamber, a valve member which is movable between open and closed positions in which a flow of pressure fluid from the interior of the chamber to the outlet is respectively permitted and prevented, the valve member having first and second oppositely disposed pressure surfaces which, in the said closed position, are respectively subjected to the pressures prevailing in the interior of the chamber and in the outlet, whereby the valve member is pressure urged towards the closed position, and means for respectively moving the valve member into the open position, the outlet having at least one vent therein to reduce the pressure acting on the said second pressure surface, whereby to assist closing movement of the valve member, a portion only of the fluid in the outlet passing to said vent.
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